Calf pain when walking: claudication, clots and other causes

Calf pain can come from the muscle itself, the blood vessels supplying it, the veins draining it or the nerves that run down from the lower back. The most useful question is what the pain does: does it arrive predictably after a certain distance and fade quickly with rest, does it persist at rest, is it confined to one swollen leg, or does it run down the back of the leg from the buttock?

The first pattern, pain that builds with walking and eases within minutes of stopping, is the textbook sign of reduced arterial blood flow to the leg muscles. The NHS calls the medical term intermittent claudication, says the pain can affect one or both legs and that it usually goes away after a few minutes when you rest. NICE CKS describes it as the most common symptom of peripheral arterial disease, with diminished circulation causing pain in the lower limb on walking or exercise that is relieved by rest.

The NHS explains that peripheral arterial disease (PAD) is a common condition where a build-up of fatty deposits in the arteries restricts blood supply to the leg muscles. Many people with PAD have no symptoms at all. Others notice, in addition to the walking ache, hair loss on the legs and feet, numbness or weakness in the legs, brittle slow-growing toenails, ulcers on the feet and legs that do not heal, changes in skin colour, shiny skin, erectile dysfunction in men and wasting of the leg muscles.

The NHS names smoking as the most significant risk factor, followed by type 1 and type 2 diabetes, high blood pressure, high cholesterol and growing older. NICE CKS lists a history of smoking, diabetes, hypertension and hypercholesterolaemia as strong risk factors and notes that some people present with atypical symptoms, so the textbook picture is not always present.

PAD is usually diagnosed by a physical examination by a GP and by comparing the blood pressure in the arm and the ankle, called the ankle brachial pressure index. NICE CKS says a reading of 0.79 or lower suggests PAD. The NHS says treatment is largely lifestyle change and medication, with regular exercise and not smoking the main lifestyle changes, and that medicine and, in some cases, surgery can improve blood flow.

Pain in the calf with activity is not always arterial. The table summarises the features the NHS and NICE CKS describe for the main alternatives, which a clinician will weigh against one another.

The NHS says that critical limb ischaemia is an extremely serious complication of PAD. Its symptoms include severe burning pain in the legs and feet that continues even at rest, skin turning pale, shiny, smooth and dry, wounds or ulcers that do not heal, loss of muscle mass and, in the worst cases, skin that turns cold, numb, red and then black. It advises contacting a GP immediately, or calling 111 if that is not possible.

NICE CKS describes acute limb ischaemia as a sudden decrease in blood flow and lists its features as pain, pallor, pulselessness, coldness, pins and needles and loss of power, with emergency assessment by a vascular specialist advised.

For a possible clot the NHS says to ask for an urgent GP appointment or get help from NHS 111, and to call 999 or go to A&E if pain and swelling come with breathlessness or chest pain, because a clot can travel to the lungs. For sciatica it lists numbness around the genitals or bottom, difficulty controlling urine or bowels, or weakness in both legs as reasons for A&E or 999.

Make a note of how far you can walk before the pain begins, how long it takes to ease, and whether it ever occurs at rest or at night. This is exactly the kind of detail that helps a GP separate arterial, nerve and muscle causes. The NHS says you should see a GP if you experience recurring leg pain when exercising.

If PAD is confirmed, NICE CKS says management of intermittent claudication should include offering a supervised exercise programme if available, and that people with PAD should be offered information, advice and treatment for secondary prevention of cardiovascular disease. The NHS adds that PAD is not immediately life-threatening, but the atherosclerosis behind it can lead to serious problems such as heart attack and stroke, which is why the diagnosis matters beyond the leg itself.